Yellow to brown dye.



UNITED STATES PATENT orrron.

AUGUST BLANK AND WTJADIMIR RODIONOW, OE: LEVERKUSEN, NEAR COLOGNE, A GERMANY, ASSIGNORS TO 'FARBENFABRIKEN VORM. FRIEDB. BAYER & (10., OF

ELBERFELD. GERMNY, A CORPORATION OF GERMANY.

v YELLOW 'ro BROWN DYE.

951 044; Specification of Letters Patent. Patented Mal. 1, 1910- No Drawing. Application filed October 14, 1909. Serial no. 522,618.

To all whom it may concern:

Be it known thatwe, Auous'r BLANK and \Vmnnnn Ronroxow, chemists, citizens of,

respectively, Germany and Russia, residing atLeve-rkusen, near Colo ne, Germany, have invented new and usefu Improvements in New Dyes, of which the following is a speci- 'e have found that-new and valuable I dyestuffs are obtained by treatlng with aromatic amins the known dyestuffs which can be obtained by treating para-nitro-toluene sulfonic acid with caustic soda 'iye. These dyestuffs areknown in commerce as curcumine S, direct yellow, sun yellow etc:

They are cheniicall y 'azoxystilbene disulfonic acid or azoazoxydistilbene disulfonic acid. (Green, Journal of (."liemical Society 89 p. 1610). g I

The new dyestuffs thus obtained are after .heing dried and pulverized brownish pow ders soluble 11) water with from a yellow' water areadded. The resulting mixture is then heated to boiling for 20 hours in a' vessel provided with a. reflux condenser arid a stirrer. The solution is neutralizedwith mineral acid 'and the dyestufi' is precipitated with salt. It is after-being dried and ulverizede yellowish-brown powder whic is solublein water with a yellow color and wl 'ch is acid with a bluish-red color-being precipitat-ed in the shape of brown flakes by the addition of water. It dyes unmordanted cotton yellow-shades.

Instead of direct yellow otlierof the above mentioned dies or other amins may be used c. g. para-amino-phenol, l-n'aphthylamin, l-naphthylainin-4-sulfonic acid, 2-naphthylamin-4 sulfonic acid etc;

-lVe claim:

tainable by condensation of aromatic amins with the dyes which are produced by treat ing paranitrotoluene sulfonic acid with caustic soda lye, which dyestuffs are after heso uble in water with a yellow to brown color and dyeing unmordanted cotton-from yellow to orange to br'wn shades fast to light and o the action 0 oxidizing agents, substan- 'tially as described.

2. The herein describednew dye'stufi obing dried and pulverized a. yellowish-brown Witnesses itiil 1 soluble in concentrated sulfuric O'r'm Komo, Cans. J. Wmon'r.

amin-4.-8-disulfonic acid, 1.8-naphthylenedi- 1. The herein described new dyestuffs ob-' in dried-and pulverized brownish powders tainable by cond ens ing direct yellow with para-phenetidin, which dyestufi is after bepowder, which 18 soluble in water with a presence of two subscribing 

